Nice price!
No eShop demos yet I believe but two or three of the games have had price promos/sales so far. Current retail demos are Zombie U, Fifa and Rayman, I believe.
Can't comment on NSMBU as I've not played it.
Re ZombieU vvvvv = yes. It is a game that goes for tension and atmosphere over all out action. An encounter with even a single zombie can go seriously wrong and end in the player's death all to easily. I have played it for 70+ hours and even now can still die from such an encounter if I'm not concentrating properly. Also, even after all this time, the cricket bat usage has still not become perfunctory for me as the risk of mistiming its usage and resultant player death is always there and it is probably the most visceral killing of a NPC I have ever played in a game. It really can be quite thrilling. Further, the cricket bat is not the ideal weapon to use on more than one zombie. Even a couple of zombies at a time can be very tricky but anymore than that is just asking for fail. I know this to my own chagrin from trying to over hoard projectile weapon ammo when I first played the game. Lastly, the risk/reward from using a projectile weapon to make encounters easier but create more noise in doing so which will attract more zombies never gets old, for me.
If you are intrigued by the game you can do far worse than try the eShop demo. I played it last night and it is a decent vertical slice of the game that gives a fair representation of its experience and gameplay. It is however tweaked for ZU newbs so the demo is easier than the actual section in the full game. Probably a wise decision but still something to bear in mind.
We get FIFA rather than NBA in Yurop

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No, it's purely to watch and/or download 18+ rated content to comply with German law. You may play the actual content whenever you like once it has downloaded. I played the Zombie U demo early evening yesterday after downloading it overnight, for example.